Based on previous studies on sports in hypertension, we expected the intervention to result in a decrease of systolic 24h-ambulatory BP (systolic ABP) of at least 6 mm Hg in the training group with no changes in the control group.16,17 This difference was considered to be clinically relevant. A sample size of 23 in each group has 80% power to detect a difference in means of 6 mmHg assuming that the common standard deviation is 7 mmHg, a baseline systolic ABP of 140 mmHg and a two-sided p<0.05. We estimated the drop-out rate to be about 15% leading to a sample size of 27 patients per group.